Photographic element comprising an aliphatic carboxylic acid aryl hydrazide and ascorbic acid

ABSTRACT

ARYL, HETEROCYCLIC OR ALIPHATIC CARBOXYLIC ACID ARYL HYDRAZIDES ARE EMPLOYED WITH ASCORBIC ACID AS A DEVELOPING AGENT COMBINATION FOR EXPOSED ELECTROMAGNETIC ENERGY SENSITIVE SILVER SALTS. THE DEVELOPING AGENT COMBINATION CAN BE EMPLOYED IN DEVELOPER SOLUTIONS, IN SILVER SALT PROCESSING SOLUTIONS, AS IN INCORPORATED DEVELOPING AGENT COMBINATION, AS A DEVELOPING AGENT COMBINATION IN DIFFUSION TRANSFER PROCESSES AND IN DRY PROCESSING TECHNIQUES. THE COMBINATION CAN BE LOCATED IN THE SAME OR DIFFERENT LAYERS OF A PHOTOGRAPHIC ELEMENT, OR THE HYDRAZIDE CAN BE LOCATED IN THE PHOTOSENSITIVE EMULSION LAYER AND THE ASCORBIC ACID LOCATED IN AN ACTIVATOR SOLUTION. THE PROCESS OF DEVELOPING EXPOSED PHOTOGRAPHIC ELEMENTS IN THE PRESENCE OF THE HYDRAZIDES AND ASCORBIC ACID IS DISCLOSED.

May 1, 1973 0 v 5 ETAL 3,730,727

PHOTOGRAPHLC ELEMENT COMl'HlSiNG AN ALJPHATIC CARBOXYLIC ACID ARYL HYDRAZIDE AND ASCORBIC ACID Filed March 11. 1971 DE/VS/TY 20 TIME //V MINUTES FEEDER/C R. BEAN /5'MAEL OL/VAHES GRANT M. HA/ST INVENTORS BY W A TTORNEY United States Patent 3,730,727 PHOTOGRAPHIC ELEMENT COMPRISING AN ALIPHATIC CARBOXYLIC ACID ARYL HY- DRAZIDE AND ASCORBIC ACID Ismael Adolfo Olivares, Frederic Roland Bean, and Grant Milford Haist, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y.

Filed Mar. 11, 1971, Ser. No. 123,317 Int. Cl. G03c 1/06, 1/76, 5/30 US. C]. 96-95 6 Claims ABSTRACT OF THE DISCLOSURE Aryl, heterocyclic or aliphatic carboxylic acid aryl hydrazides are employed with ascorbic acid as a developing agent combination for exposed electromagnetic energy sensitive silver salts. The developing agent combination can be employed in developer solutions, in silver salt processing solutions, as an incorporated developing agent combination, as a developing agent combination in diffusion transfer processes and in dry processing techniques. The combination can be located in the same or different layers of a photographic element, or the hydrazide can be located in the photosensitive emulsion layer and the ascorbic acid located in an activator solution. The process of developing exposed photographic elements in the presence of the hydrazides and ascorbic acid is disclosed.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to photographic compositions and especially to novel developer compositions exhibiting improved photographic properties. The invention especially relates to photographic developing solutions, processing solutions, photographic elements and photographic emulsions containing a novel developing agent combination.

Description of the prior art Hydrazines and hydrazine derivatives have been employed in photographic emulsions or developers for many purposes. Mees, The Theory of the Photographic Process, 3rd edition, 1966, page 281, however, discloses that few developing agents of importance have been found among the hydrazines and/ or their derivatives.

The use of hydrazides in developing solutions and/or silver halide emulsions is particularly known, however, the compounds are employed as supplemental developers or in a non-developing function, but not as a principal developing agent. Trivelli et al., US. Pat. 2,419,975, issued May 6, 1947, for example, describes a method of improving the sensitivity of a silver halide photographic layer by incorporating therein a semicarbazide. Honig et al. US. Pat. 3,386,831, issued June 4, 1968, describes methods of stabilizing photographic silver halide emulsions with acyl phenyl hydrazides. Whitmore US. Pat. 3,227,- 552, issued Jan. 4, 1966, discovered that a Wide variety of hydrazones and hydrazides can be employed as supplemental developing agents in the process of preparing photographic direct positive color images.

Although some hydrazines are interesting, from a historical and theoretical point of view, as developing agents hydrazines and their derivatives have generally not been found to be useful.

There is a constant search for compounds which can develop not only exposed photographic silver halide, but additionally other photographic silver salts to visible images. The developing agent should be reasonably fast and should produce images evidencing strong image discrimination with little propensity for staining.

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In our cofiled application Ser. No. 123,450, entitled, Photographic Compositions, Elements and Process, hydroxy substituted aliphatic carboxylic acid/aryl hydrazides are shown to be suitable developing agents for exposed silver salts. These developing agents are disclosed as showing little propensity for staining, as being reasonably fast without the presence of secondary developing agents and to produce images having good sensitometric properties.

It is apparent, in the art, that there is a need to further improve the speed, particularly for photographic elements to be processed in the rapid machine processing systems, and to improve the sensitometric properties of photographic developers.

It is, furthermore, desirable to find developing agents that can advantageously be employed in a variety of photographic products, for example, in photographic developer and processing solutions, as incorporated developing agents in photographic emulsions, in photographic products that may be processed according to the so-called dry processing techniques, in photographic diffusion transfer products, etc.

Developing agents having such universal applications are highly unusual. A developing agent, for example, which is desirably employed in a developing solution can be useless as an incorporated developing agent, i.e. one incorporated in a photographic emulsion, since the developing agent may not be stable in the emulsion. A developing agent, as incorporated, may cause spontaneous reduction (fogging) or may be lost by oxidation. A developing agent which is incorporated in a photographic element adapted for wet processing can be undesirable for incorporation in a photographic element adapted for dry processing since most developing agents have a tendency to induce staining unless washed out from the elements upon processing.

SUMMARY OF THE INVENTION In accordance with this invention, photographic silver salt developing compositions are provided which are a combination of an aliphatic, aryl or heterocyclic carboxylic acid aryl hydrazides and ascorbic acid. It has been unexpectedly discovered that the developing compositions of this invention can beemployed in a variety of photographic products as described herein. The utility of the developing compositions in the many photographic products is unexpected and unobvious since many of the hydrazides disclosed herein are not selective developers, i.e. one that distinguishes between exposed or unexposed silver halide or exhibit very little selective developing activity. Hydrazides such as those of the prior art or aliphatic carboxylic acid aryl hydrazides not within the scope of this invention do not manifest any substantial developing activity. Furthermore, combinations of many fogging agents, such as hydrazine or phenylhydrazine with ascorbic acid does not increase the selectivity of development; that is, it is unexpected that the combination of ascorbic acid with a hydrazide should produce a more selective developer.

It is, therefore, an object of this invention to provide novel photographic silver salt developing agent combinations capable of providing increased speeds and strong image discrimination.

A further object of this invention is to provide photographic silver salt processing compositions which provide desired sensitometric properties and developing action without objectionable stain.

Another object is to provide improved photographic elements and/or emulsions having a developing agent combination incorporated therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The above and other objects of the present invention are accomplished by providing a novel developing agent composition which comprises: (a) an aliphatic, aryl or heterocyclic carboxylic acid aryl hydrazide, and (b) ascorbic acid. Preferred hydrazides employed in this invention are represented by the general structural formula:

R;NH-NH- 'i-R wherein R is an aryl group including substituted aryl groups as exemplified by phenyl, naphthyl, alkaryl, such as tolyl, xylyl, mesityl, ethylphenyl, propylphenyl, halide substituted phenyl such as bromophenyl, dichlorophenyl, carboxyphenyl and the like; and R is an aliphatic group, including substituted aliphatic groups, as exemplified by alkyl, such as methyl, ethyl, propyl, butyl, alicyclic substituted alkyl such as cyclopentylethyl, hydroxyalkyl such as hydroxyethyl, hydroxypropyl, tris(hydroxymethyl)butyl, carboxyalkyl such as carboxymethyl, carboxyethyl, carboxyphenyl, unsaturated hydrocarbons, including substituted unsaturated hydrocarbons, such as vinyl, allyl, phenylallyl, alicyclic group, such as cyclopentyl, methylcyclopentyl, cyclohexyl, cyclohexylbromide, unsaturated alicyclic such as cyclopentyl, cyclohexenyl, and the like; an aryl group, including substituted aryl, as exemplified by phenyl, naphthyl, alkaryl such as tolyl, xylyl, mesityl, ethylphenyl, propylphenyl, halide substituted phenyl such as bromophenyl, dichlorophenyl, carboxyphenyl and the like; and a heterocyclic group, e.g. Z-furyl, thienyl, benzothienyl, pyridyl, quinolyl, and the like. In a preferred aspect of this invention R can have from 1 to about 12 carbon atoms and R can have from 1 to about 10 carbon atoms, however, groups having a greater number of carbon atoms are suitably employed; the selection of the hydrazides being within the skill of a practitioner in the art.

In another preferred aspect of this invention the hydra- Zides can be represented by the general structural formula:

(II) 0 R:

wherein R is an aryl grouping as described supra and R R and R each alone can be hydrogen, methylol, a lower alkyl such as methyl, ethyl, propyl, and the like, or R and R form a saturated ring system, with the condition that at least one of R R and R is methylol.

Illustrative, but non-limiting examples of hydrazides which may be employed according to the invention are:

2,2,2-tris (hydroxymethyl acetyl-fl-phenylhydrazide 2,2-bis(hydroxymethyl)propionyl-,B-phenylhydrazide 3-hydroxypivalyl-fl-phenylhydrazide 2,2-bis (hydroxymethyl propionyl-fl-p-tolylhydrazide 1-benzoyl-fl-phenylhydrazide 1-forrnyl-2-phenylhydrazide 1-acetyl-Z-phenylhydrazide I-chloroacetyl-Z-phenylhydrazide Hydracrylic acid, Z-phenylhydrazide SQ-d me fl l acid; ph hy azide 3-methylcinnamic acid, phenylhydrazide 3-hydroxybutyric acid, phenylhydrazide 3-hydroxybutyric acid, o-tolylhydrazide S-hydroxybutyric acid, 2,6-dimethylhydrazide 2,2-bis(hydroxymethyl)propionyl-B-o-tolylhydrazide 2,2-bis hydroxyrnethyl) propionyl-(i-o-brornophenyl hydrazide 2,2-bis (hydroxymethyl propionyl-fl-2,5-chlorophenylhydrazide The hydrazides employed in this invention are prepared by methods well known in the art. The hydrazides can be prepared according to methods described in, for example, Donovan, U.S. Pat. 2,912,461.

Although it is preferable to use ascorbic acid in combination with the hydrazides other analogs of ascorbic acid may be suitably employed, for example, isoascorbic acid, a-erythroascorbic wascorbic acid, D-glucoascorbic acid, 6-deoxy-a-ascorbic acid, ot-rhamnoascorbic acid, OL-flJCOaSCOTblC acid, D-glucoheptoascorbic acid and the like. The compounds can be employed as their acid or their ester or ketal derivatives. Other analogs of ascorbic acids which may be suitably employed are described in U.S. Pat. 2,688,549 of James and Reynolds, issued Sept. 7, 1954. Accordingly, the term ascorbic acid as used in the specification and claims is understood to include the analogs and stereoisometric forms of ascorbic acid.

A significant feature and advantage of the developing agent combination is its substantially low propensity for staining, hence the developing agent combination need not be washed from the emulsion following processing. This feature is particularly advantageous in rapid machine processing and in photographic elements adapted for dry processing. A second significant feature and advantage is the low fogging propensity and the very high image selectivity obtained when the hydrazides are employed with ascorbic acid. The very high selectivity is unexpected and appears to be specific to the disclosed combination. For example, neither does ascorbic acid substantially reduce the fog of conventional developing agents, nor do conventional developing agents effect a substantial reduction of the fogging propensity of hydrazides. This latter aspect of the invention is illustrated by Example 4 which follows.

Another significant feature and further advantage of the disclosed developer combinations is its substantial stability when incorporated in a photographic element. They neither cause nor induce spontaneous reduction, nor are the developing agent combinations lost by oxidation; hence the shelf life of a photographic product is substantially extended.

Still another significant feature of the developing agent combination employed in this invention is the improved solubility over many hydrazides and hydrazines of the prior art, this feature is especially noticed with the hydrazines encompassed by Formula II.

The mole ratio of hydrazide to ascorbic acid can vary over a wide range. The selection being within the skill of the practitioner in the art. The selection of ratios can depend on a number of factors such as the type of photographic system being developed, the method of development, whether the developer combination is incorporated or part of a developer or processing solution or package. A preferred mole ratio of hydrazide to ascorbic acid is 1:20 to about 20:1. Another preferred ratio is 1:5 to 2: 1. A desirable ratio is 1:1 on a molar basis.

The novel developing agent combinations, of this invention can be suitably utilized in any of a variety of locations with respect to a photographic system. They can be employed in photographic processing and/ or developing solutions, for example, in an aqueous alkaline developer composition. They can be incorporated into a layer of a photographic element such as a silver halide emulsion layer, an overcoat layer or an interlayer of a photographic e ement. T ey can be utilized in. a de e p r co p sition intended for use in a diffusion transfer process or they can be utilized in one or more layers of a photographic element employed in a diffusion transfer process. Diffusion transfer processes and photographic elements in which the developing agents are useful are described, for example, in U.S. Patents 2,352,014 of Rott, issued June 20, 1944; 2,543,181 of Land, issued Feb. 27, 1951; and 3,337,342 of Green, issued Aug. 22, 1967. The developing agent combinations of this invention can also be employed in socalled high-speed diffusion transfer processes as described, for example, in U.S. Patent 3,326,683 of Land et al., issued June 20, 1967; or in other types of diffusion transfer processes such as those described in U.S. Patents 2,857,274 of Land et al., issued Oct. 21, 1958; 3,020,155 of Yackel et al., issued Feb. 6, 1962; 2,584,030 of Land, issued J an. 29, 1952; and 2,923,623 of Land, issued Feb. 2, 1960. These patents describe typical photographic products suit able for diffusion transfer systems comprising a combination of (a) a photosensitive element which comprises a support having thereon at least one photosensitive silver salt emulsion layer (b) an image-receiving layer, and (c) a rupturable container containing an alkaline processing composition comprising a silver halide developing agent, and typically a silver halide solvent. They can be located in the same or contiguous layers of a photographic element or the hydrazide can be located in the photosensitive emulsion layer and the ascorbic acid located in the activator solution or layer. The latter arrangement is especially desirable since it allows for the most optimum keeping conditions. Hence in a preferred embodiment there is provided a photographic element comprising a support having thereon at least one photographic silver salt emulsion layer containing an aryl, heterocyclic or aliphatic carboxylic acid aryl hydrazide described herein; and an activator layer or solution containing ascorbic acid. The novel developing agent combinations of this invention can be utilized in combination with photosensitive elements which are adapted for processing by the so-called dry photography (heat) development methods. No liquids, vapor or other processing aids need be employed in order to obtain a high image density or desirable image tone in the photosensitive element having incorporated therein the novel developers of this invention. Dry photography processes are described, for example, in U.S. Patents 3,457,075 of Morgan et al., issued July 22, 1969; 3,152,903 of Sheppard et al., issued Oct. 13, 1964 or 3,152,904 of Sorensen et al., issued Oct. 13, 1964.

The developing agent combinations employed in the practice of this invention can be employed for developing an image in a wide variety of photographic emulsions. The silver halide emulsions employed can comprise silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof. The emulsions may be coarse or fine grain and can be prepared by any of the well-known procedures, e.g. single jet emulsions, double jet emulsions, such as Lippmann emulsions, ammoniacal emulsions, thiocyanate or thioether ripened emulsions such as those described in Nietz et al. U.S. Patent 2,222,264, issued Nov. 4, 1940; IllingsworthTLS. Patent 3,320,069, issued May 15, 1967; and McBride U.S. Patent 3,271,157, issued Sept. 6, 1966. Surface image emulsions may be used or internal image emulsions such as those described in Davey et al. U.S. Patent 2,592,250, issued Apr. 8, 1952; Porter et al. U.S. Patent 3,206,313, issued Sept. 14, 1965; Berriman U.S. Patent 3,367,778, issued Feb. 6, 1968; and Bacon et al. U.S. Patent 3,447,927, issued June 3, 1969. If desired, mixtures of surface and internal image emulsions may be used as described in Luckey et al. U.S. Patent 2,996,382, issued Apr. 15, 1961. Negative type emulsions may be used or direct positive emulsions such as those described in Leer makers U.S. Patent 2,184,013, issued Dec. 19, 1939; Kendall et al. U.S. Patent 2,541,472, issued Feb. 13, 1951;

Berriman U.S. Patent 3,367,778, issued Feb. 6, 1968; Schouwenaars British Patent 723,019; Illingsworth et al. French Patent 1,520,821; Ives U.S. Patent 2,563,785, issued Aug. 7, 1951; Knott et al. U.S. Patent 2,456,953, issued Dec. 21, 1968; and Land U.S. Patent 2,861,885, issued Nov. 25, 1958. The emulsions may be regular grain emulsions such as the type described in Klein and Moisar, J. Phot. Sci., vol. 12, No. 5, Sept./Oct., 1964, p. 242-251.

The developing agent combinations or reducing agent combinations as commonly referred to in the art of dry photography have unexpectedly found to be suitable as primary developing components in accordance with this invention and can be employed in combination with any silver salt developing agent. Suitable silver halide developing agents which can be employed with the developing agents of the invention include, for example, polyhydroxybenzenes, such as hydroquinone developing agents, e.g., hydroquinone; alkyl substituted hydroquinones such as t-butyl-hydroquinone, methylhydlroquinone and 2,5-dimethyl hydroquinone; catechols and pyrogallol; halo substituted hydroquinones such as chlorohydroquinone or dichlorohydroquinone; alkoxy substituted hydroquinones such as methoxyhydroquinone or ethoxyhydroquinone; aminophenol developing agents, such as 2,4-diarninophenols, e.g., 2,4-diamino-6-methylphenol, and methylaminophenols; hydroxyamines such as N,N-di(2-ethoxyethyl)hydroxyamine; 3-pyrazolidone developing agents such as 1-phenyl-3-pyrazolidone, including those described in British Patent 930,572; acyl derivatives of p-aminophenol such as described in British Patent 1,045,303; hydroxytetronic acid and hydroxytetronimide developing agents; reductone developing agents such as anhydrodihydropyrrolidino hexose reductone and the like.

In accordance with another embodiment of the invention, photographic developer compositions are provided comprising the silver salt developing agent combination described herein.

The photographic developer compositions can include ingredients commonly employed for processing photographic elements in addition to the developing agents, e.g., stabilizer compositions, monobaths, activator compositions, hardener compositions and the like.

The photographic developer compositions according to the invention can contain a silver halide solvent. A variety of silver halide solvents are suitable, such as alkali metal and ammonium thiocyanates, e.g., sodium and potassium thiocyanate and ammonium thiocyanate, alkali metal thiosulfates, such as sodium thiosulfate and potassium thiosulfate, thiourea compounds, and the like.

The developing agent combination of the invention can be employed in processing compositions in any form suitable for developing an exposed photographic element. For example, the developing agent combination of this invention can be employed alone or with one or more auxiliary developing agents edscr-ibed herein. The de veloping agent combination can be provided as an aqueous silver halide developer solution or liquid concentrate; as a component of a solid particulate composition suitable for dissolving in a solvent such as an aqueous solvent; as a viscous composition containing various thickening agents; as a packaged component of a kit for mixing with various processing agents or as a component of a fusible solid such as solid containing a homogeneous mixture of an alkylene oxide polymer and developer combination of the invention said fusible solid melting above about room temperature, and the like.

A further aspect of the invention is in a photographic process for developing exposed silver salt layers of a photographic element, said process comprising contacting the silver salt layer with the developer combination of this invention in the presence of an alkaline development activator. In accordance with this aspect, the invention can comprise a process of developing the exposed silver salts in a photographic silver salt layer by contacting the 7 silver salt layer with a processing composition containing a silver halide solvent and the novel silver halide developer.

The process according to this aspect can also employ other silver halide developing agent, as described herein, as an auxiliary developing agent. The auxiliary developing agents can be located in a layer of a photographic element to be processed and/ or in the silver halide processing composition. Developing action is elfected upon contact of the developing components of the invention with a suitable activator.

Any alkaline developer activator can be employed to activate the developing agents of the invention in nondry processing photographic processes so long as the activators provide the desired pH. These include those commonly employed in the photographic art as development activators, such as inorganic alkali, e.g., alkali metal hydroxide including sodium hydroxide, potassium hydroxide and lithium hydroxide, alkali metal carbonate, such as sodium carbonate, sodium bicarbonate, fuming ammonia, and the like as well as organic alkali such as organic amines and aminoalkanols, e.g., ethanol amines and aminodiethanolamino or morpholine. The concentration of development activator can vary depending on the various components of the system, the photographic emulsion employed, the desired image, and the like. A concentration is usually employed which provides a pH of at least about 8, typically from about 10 to about 14, and preferably about 12 to about 14.

In another embodiment of the invention photosensitive elements are provided, said elements comprising a support, at least one silver salt layer and incorporated in said element, a photographic silver salt developing combination of this invention. The developer combination can be employed in a photographic silver salt emulsion layer, an overcoat layer, a layer under the emulsion layer, or virtually any of the layers contiguous to the silver salt to be developed.

The developing agent combination of the invention can be employed in photographic elements designed for processing in stabilization type processing. For example, they can be incorporated in one or more layers of a photo graphic element which is exposed, activated by contact with alkaline activator, and then contacted with a thiocyanate or thiosulfate solution, such as an ammonium thiocyanate, or they can be incorporated in the alkaline activator. Such processes are described, for example, in U.S. Pat. 3,326,864 of Nishio, issued June 20, 1967; British Pat. 1,004,302; French Pat. 1,516,556 of Fassbender; and in an article by H. D. Russell, E. C. Yackel and J. M. Bruce in the PSA Journal, August 1950, pages 59-62, entitled, Stabilization Processing of Films and Papers.

The developing agent combination of this invention as described herein can be used in layers of photographic elements or processing solutions intended for use in monobath processing such as described in U.S. Pat. 2,875,048 of Haist et al., issued Feb. 24, 1959, and British Pat. 1,063,844 of Beavers et al., issued Mar. 30, 1967, and in web-type processing, such as described in U.S. Pat. 3,179,- 517 of Tregillus et al., issued Apr. 20, 1965.

The developing agent combinations of this invention can be employed in a photographic silver salt emulsion designed for difiusion transfer processing and/or in a developer composition designed for developing and stabilizing the element. A typical developer composition is disclosed in U.S. Pat. 3,120,795 of Land et al., issued Feb. 11, 1964.

Hence, in accordance with an aspect of the invention there is accordingly provided in combination (a) a photographic element comprising a photographic silver salt layer, (b) a viscous processing composition, within a releasing means, e.g., a rupturable container, comprising:

(i) A silver halide solvent,

(ii) An alkaline development at tivator,

(iii) Optionally, a 3-pyrazolidone developing agent, a diaminophenol developing agent or other auxiliary developing agent described herein, and

(iv) The novel developing combination of this invention, and (c) an image receiving layer comprising development nuclei, especially palladium development nuclei, dispersed in a polymeric binder.

Albeit the developing agent combination is generally located in a relasing means, they can be suitably employed in a variety of locations with regard to a difiusion transfer system. The novel developer combination can be provided in the silver salt layer or emulsion, in a layer near to the silver salt layer, in the image receiving layer containing silver precipitating nuclei or development nuclei as well as in the rupturable container.

In accordance with a typical dilfusion transfer process a photographic element is exposed imagewise, the exposed silver halide is developed at a pH above 8, typically above 10 and preferably at a pH of about 12 to about 14, in the presence of the novel developers, the unexposed silver salts in the photosensitive silver salt layer is contacted with a silver halide solvent to form an imagewise distribution of a silver complex in the unexposed areas of said photographic silver salt layer; and at least part of the silver complex is transferred to an image receiver layer contiguous to the photosensitive layer, said receiver layer containing development nuclei, thereby forming a visible image on said receiver layer.

Processing conditions, time of development, and the like can vary depending on the desired image, the particular components of the described element, processing composition, and image receiver. Typically processing is carried out under normal atmospheric conditions and is completed within about 60 seconds, e.g., within about 10 seconds.

Usually the silver halide solvent will be sodium thiosulfate; however, various organic silver halide complexing agents such as those described by Haist et al., Phot. Sci. Eng, 5, 198 (1961) and in Kodak French Pat. 1,312,687, issued Nov. 12, 1962, and Belgian Pat. 606,- 559 of Ulrich et al., issued July 26, 1960, and similar agents can also be used.

The light-sensitive element, receiving element or processing composition can also contain toning agents such as, for example, polyvalent inorganic salts of the type described in U.S. Pat. 2,698,236 of Land, issued Dec. 28, 1954, silica as described in U.S. Pat. 2,698,237 of Land, issued Dec. 28, 1954, and heterocyclic mercaptans such as the mercapto azoles, e.g., mercapto diazoles, mercapto triazoles and mercapto tetrazoles.

Typically, the developing agent combination is provided in a viscous liquid photographic developer composition comprising (a) a silver halide solvent, and (b) the silver halide developer combination of the invention. The viscous liquid photographic developer composition can also contain additional silver halide developing agents, as described herein, especially a 3-pyrazolidone silver halide developing agent.

A viscous liquid photographic developer composition can comprise a viscous monobath. Suitable viscous monobaths are described, for example, in the Monobath Manual, Morgan & Morgan, New York, by Grant M. Haist (1966).

Typically, a suitable developer composition according to the invention can comprise a viscous developer containing:

(a) A silver halide solvent, such as sodium thiosulfate;

(b) A diaminophenol auxiliary developing agent, such as 6-methoxy-2,4-diaminophenol or 6-ethyl-2,4-diaminophenol or a 3-pyrazolidone auxiliary developing agent such as 1-phenyl-3-pyrazolidone or 1-phenyl-4,4-dimethyl-3-pyrazolidone;

(c) The developer composition of the invention;

(d) An alkaline development activator, and

(e) A thickening agent, such as a cellulose derivative, e.g., hydroxyethyl cellulose and/or carboxymethyl cellulose.

Suitable viscosities for the viscous composition can vary over a wide range. The viscosity is usually from about to about 1000 cps. Various thickening agents are suitably employed in the described processing compositions and processes of the invention. Any of those commonly employed in difiusion transfer photographic systems can be employed. These include those described in the art, such as cellulose derivatives, e.g., hydroxyethyl cellulose and/or carboxymethyl cellulose.

In another aspect of this invention, it has been discovered that the developing agent combinations described herein can be utilized in the photographic process generally referred to as dry photography. The elements employed in dry photography are photosensitive, i.e., a latent image is formed imagewise in the exposed areas of a silver salt layer, and thermosensitive, i.e., substantially permanent, visible images of photographic sharpness and high visual contrast can be produced often within seconds through the mere application of heat. The dry photographic elements are developed by heating to within a temperature range of from about 80 C. to about 250 C.

Typically a dry photographic element comprises a support having thereon an oxidation-reduction image forming combination said combination comprising a silver salt, preferably an organic silver salt, and a reducing agent, and a catalyst for the oxidation-reduction image forming combination.

In accordance with an aspect of the invention, the hydrazides in combination with ascorbic acid or its analogs can be employed as the reducing agent or composition in the dry photographic element.

Other reducing agents as described herein can be employed in combination with the developing agent combination of this invention, and include, for example, the prior art silver halide developing agents and/or substitute'd phenols and naphthols described in De Mauriac, U.'S. Ser. No. 33,964, filed May 1, 1970, now US. Pat. 3,672,904.

As the oxidizing agent, of the oxidizing-reduction image forming combination, a silver salt of an organic acid is preferably employed. The silver salt of the organic acid should be resistant to darkening under illumination to prevent undesired deterioration of a developed image. An especially suitable class of silver salts of organic acids is the water insoluble silver salts of long-chain fatty acids which are stable to light. Typically, the silver salts include silver behenate, silver stearate, silver oleate, silver laurate, silver hydroxystearate, silver caprate, silver myristate, and silver palmitate. Other suitable oxidizing agents are silver benzoate, silver phthalazinone, silver benzotriazole, silver saccharin, silver 4-n-octadecyloxydiphenyl-4-carboxylic acid, silver orthoamino-benzoate, silver acetamidobenzoate, silver furoate, silver comphorate, silver p-phenylbenzoate, silver phenyl acetate, silver salicylate, silver butyrate, silver terephthalate, silver phthalate, silver acetate, and silver acid phthalate. Nonsilver salts can be employed as oxidizing agents, such as zinc oxide, gold stearate, mercuric behenate, auric behenate and the like, however, silver salts are generally preferred.

Typically, a photosensitive salt is present in the dry photographic elements in minor or catalytic amounts. A suitable concentration range of the catalyst is generally from about 0.01 to about 0.50 mole of photosensitive silver salt per mole of oxidizing agent. Suitable silver salts include photosensitive silver halides, e.g., silver chloride, silver bromide, silver bromoiodide, silver chlorobromoiodide, or mixtures thereof. The photosensitive silver halide can be coarse or fine-grain, very fine-grain emulsions being especially useful. The emulsion containing the photosensitive silver halide can be prepared by any of the well-known procedures in the photographic art, such as single-jet emulsions, double-jet emulsions, such as Lippmann emulsions, ammoniacal emulsions, thiocyanate or thioether ripened emulsions, such as those described in US. Pat. 2,222,264 of Nietz et al., issued Nov. 14, 1940; US. Pat. 3,320,069 of Illingsworth, issued May 15, 1967, and US. Patent 3,271,157 of McBride, issued Sept. 6, 1966. Surface image silver halide emulsions can be used. If desired, mixtures of surface and internal image silver halide emulsions can be used as described in US. Patent 2,996,382 of Luckey et al., issued Apr. 15, 1961. Negative type emulsions can be used. The silver halide emulsion can be a regular grain emulsion such as described in Klein and Moisar, Journal of Photographic Science, volume 12, No. 5, SeptemberOctober (1964), pages 242-251.

The dry photographic elements preferably contain an activator-toning agent. Suitable activator-toning agents which can be employed include cyclic imides such as:

phthalimide, N-hydroxyphthalimide, N-potassium phthalimide, N-mercury phthalimide, succinimide, and N-hydroxysuccinimide.

Other activator-toning agents can be employed in combination with or in place or the cyclic imides. Such other activator-toning agents are generally heterocylic compounds containing at least two hetero atoms in the heterocyclic ring, at least one being nitrogen. Illustrative compounds include phthalazinone, phthalic anhydride, 2-acetylphthalazinone and 2-phthylylphthazinone. Grand, US. Patent 3,080,254, issued Mar. 5, 1963, and Workman US. Patent 3,446,648, issued May 27, 1969, describe suitable activator-toning agents.

Activator-toning agents are suitably employed at a concentration of about 0.10 mole to about 1.05 moles per mole of oxidizing agent, However, lower and higher concentrations can be employed.

This invention can be further illustrated by the following examples of preferred embodiments thereof, although it will be understood that these examples are included merely for illustrating this invention.

EXAMPLE 1 Strips of a fine grain silver bromoiodide emulsion are exposed behind a step wedge to produce a sensitometric exposure and developed at 20 C. in one of the following developing compositions:

Water to 1 liter.

The pH is adjusted to 11.5 with acetic acid.

The developing agents tested are :1

(1) Phenylhydrazine;

(2) 2,2 bis(hydroxymethyl)propionyl B phenyldrazide;

(3) 2,2,2 tris(hydroxymethyl)acetyl B phenylhydrazide.

The activity of the developer compositions A and B are measured in terms of the time required to obtain a density of 1.5 and 2.0 respectively on the fourth step of the sensitometric strip. The corresponding density of the un- TABLE I Time, Image Fog Developer (minutes) density density 10.0 1.50 1 plus ascorbic acid 5.3 2.00 4. 1 1. 50 2 plus ascorbic acid 3. 3 2.00 3. 4 1. 50 3 plus ascorbic acid 2. 9 2.00

EXAMPLE 2 Strips of a fine grain silver bromoiodide emulsion are exposed and developed as in Example 1 employing one of the following developer solutions:

Developer Solution 1 Mole Phenylhydrazine 0.02 Sodium sulfite 0.02 Trisodium phosphate 0.2 Water to 1.0 liter. pH 11.5.

Developer Solution 2 Same as 1 except 2,2-bis(hydroxymethyl)propionyl-fiphenyl hydrazide is substituted for phenylhydrazine.

Developer Solution 3 Same as 2 plus 0.02 mole of ascorbic acid.

The activity of the developer solutions are measured in terms of the time required to obtain a density of 2.0 on the fourth step of the sensitometric strip. The corresponding density of the exposed area (fog) is also read. The results are shown graphically in FIG. 1. Curve 1, corresponding to developer solution 1, is a plot of image density vs. time and curve 1F is the corresponding fog density vs. time. Poor image discrimination is illustrated by the narrow separation of curves 1 and IF. Curve 2, corresponding to developer solution 2, is a plot of image density -vs. time and 2F is the corresponding fog curve. Curve 2 illustrates the improvements disclosed in our so filed application Ser. No. 123,450, entitled, Photographic Compositions, Elements and Process. The curve clearly indicates an improvement in speed and a substantial increase in image discrimination as measured by the distance between curves 2 and 2F. Curves 3 and 3F are the corresponding image density and fog density curve vs. time for developer solution 3. This curve in a noticeable manner illustrates the improvements obtained in accordance with this invention. Image development substantially more active, however, fog density is substantially low.

When ascorbic acid is employed as the sole developing agent about 7.5 minutes are required to produce an image density of 2.0 as compared with 3.3 minutes required by developer solution 3.

EXAMPLE 3 This example illustrates that not only hydroxy substituted aliphatic carboxylic acid aryl hydrazides are successfully employed as developers but that other hydrazides encompassed by Formula I in combination with ascorbic acid can be employed. The hydrazides show good image discrimination.

Strips of a fine grain silver bromoiodide emulsion are exposed and developed under conditions similar to that of Example 1. Half the developer solutions contain 0.02 M concentration of developing agent described in Table II while half contain in addition 0.02 M ascorbic acid. The data described in Table II is obtained at an image density of 2.0.

Fog

Relative Hydrazide fogging Hydrazide and ascorbic 2/1 x 100, R alone (1) acid (2) percent Phenylhydrazine 1 1. 20 1. 00 83 H 1.15 0.20 17 0.75 0.13 17 0.95 0.14 15 1.04 0.13 12 .90 0.13 14 CHZCHOHCHQ .80 0.10 13 1 Not a developer of this invention.

EXAMPLE 4 This example illustrates that developing agents of the prior art such as hydroquinone and the like do not successfully restrain fog with the hydrazides of this invention.

Strips of a fine grain silver bromoiodide emulsion are exposed and developed under conditions similar to that of Example 1. The developing agents employed are described in Table III.

TABLE III Relative amount 'Iime, of fog, Developer (minutes) Fog percent No'rE.A=Hydracrylie acid, 2-phenyl hydrazide; B=Hydraerylic acid plus Ascorbic acid; C=Hydracrylie acid plus Hydroquinone.

Table III shows that good image discrimination is not obtained when the hydrazides are in combination with a developer such as hydroquinone.

EXAMPLE 5 Use in diffusion transfer process Three separate developer solutions to be employed in a diffusion transfer process are prepared as follows:

The pH for solutions A and B are adjusted with NaOH to 13.5 and the pH of C is adjusted to 12.5.

Three separate silver chlorobromide emulsions are exposed on a process control sensitometer and contacted with a receiver layer which contains Carey Lea silver on a reflection support. The receiver is bathed in one of the above formulations for two minutes. The receiver and negatives are laminated together for a period of 10 minutes at room temperature. Duplicates are made, one of which receives no further treatment on delamination while the others are washed and dried. A dense negative and a positive of neutral tone, high contrast, low fog, and exceptionally high emulsion speed is obtained from Developer B. It is free from stain even though it receives no further washing. Developer C produces negative and positive images of high contrast and low stain, even though not subsequently washed. In contrast, Developer A, containing only the ascorbic acid, produces very weak negative and the positive has a very high minimum density.

The concentrations of the developer combination employed in accordance with the invention can vary over Wide ranges depending upon the particular photographic system. Typical of the variable which affect the concentration of the developing agents are the location in the photographic element, the developer composition, the desired image, etc. Suitable concentrations are also dependent on processing conditions, addenda present in the photographic element to be processed and/or in the processing compositions. Suitable optimum concentrations can be easily determined by those skilled in the art through routine experimentation. Typically, when a developer combination described herein is incorporated in a photographic element, the concentration can vary from about 10 to about 400 g. of developer combination per mole of silver present in the photographic element. A more preferred range is from about 40 to about 200 g. per mole of silver present. When a developer combination as described is employed in a composition for processing of a photographic element, the total concentration of developing agents can vary from about 2 to about 100 g./l. and preferably from about 5 to 40 g./l.

As employed in a dry photographic element the hydrazides of this invention can be present in an amount of from about 0.1 to about 4 moles per mole of catalyst and preferably from about 0.5 to 2 moles per mole of catalyst.

The particular time required for developing the photographic elements described herein can vary over a wide range such as from about a few seconds up to an hour or more, depending on the photographic element utilized, the desired image, the various addenda employed, etc. The optimum developing time can be obtained by routine experimentation.

Silver precipitating or development nuclei or agents which can be employed in diffusion transfer systems as described can be physical development nuclei or chemical precipitants including: (a) heavy metals in colloidal form and salts of these metals, (b) salts of amines which form silver salts and/or (c) non-diffusion polymeric materials with functional groups capable of combining with the silver amine. Suitable silver precipitating agents and/ or nuclei within the above classes include metal sulfides, selenides, polysulfides, polyselenides, thiourea derivatives, stannous halides, silver, gold, platinum, palladium, and mercury, colloidal silver and similar agents disclosed, for example, in U.S. Pat. 3,020,155 of Yackel et al., issued Feb. 6, 1962. A wide range of concentrations of the silver precipitating agents and nuclei can be employed. The concentration of silver precipitant or nuclei in the receiving layer or receiving sheet must be at least sufficient to ensure a positive and sufficient removal of undeveloped silver salt from the light-sensitive layer to be processed. Usually, the concentration of developing agent described is about 3 to about 320 milligrams per square foot of the layer containing the precipitants or nuclei.

The silver halide emulsions employed with the developers of this invention may be unwashed or washed to remove soluble salts. In the latter case the soluble salts may be removed by chill-setting and leaching or the emulsion may be coagulation washed, e.g., by the procedures described in Hewitson et al. U.S. Pat. 2,618,556, issued Nov. 18, 1952; Yutzy et al. U.S. Pat. 2,614,928, issued Oct. 21, 1952; Yackel U.S. Pat. 2,565,418, issued Aug. 21, 1951; Hart et al. U.S. Pat. 3,241,969, issued Mar. 22, 1966; and Waller et a1. U.S. Pat. 2,489,341, issued Nov. 29, 1949.

The emulsions employed with the developing agent combinations of this invention may be sensitized with chemical sensitizers, such as with reducing agents; sulfur, selenium or tellurium compounds; gold platinum or palladium compounds; or combinations of these. Suitable procedures are described in Sheppard et al. U.S. Pat. 1,623,499, issued Apr. 5, 1927; Waller et al. U.S. Pat. 2,399,083, issued Apr. 23, 1946; McVeigh U.S. Pat.

14 3,297,447, issued ]an. 10, 1967; and Dunn U.S. Pat. 3,297,446, issued Ian. 10, 1967.

Development modifiers can be employed in combination with the silver halide emulsions as described in this invention. Typical development modifiers include polyalkylene glycols, cationic surface active agents and thioethers or combinations of these as described in Piper U.S. Pat. 2,886,437, issued May 12, 1959; Dann et al. U.S. Pat. 3,046,134, issued July 24, 1961; Carroll et al. U.S. Pat. 2,944,900, issued July 12, 1960; and Gotfe U.S. Pat. 3,294,540, issued Dec. 27, 1966.

Although the developer combination greatly reduced fogging, the silver halide emulsions used in the practice of this invention can be additionally protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers each used alone or in combination include thiazolium salts described in Brooker et al. U.S. Pat. 2,131,- 038, issued Sept. 27, 1938, and Allen et al. U.S. Pat. 2,694,716, issued Nov. 16, 1954; the azaindenes described in Piper U.S. Pat. 2,886,437, issued May 12, 1959, and Heimbach et al. U .8. Pat. 2,444,605, issued July 6, 1948; the mercury salts as described in Allen et al. U.S. Pat. 2,728,663, issued -Dec. 27, 1955; the urazoles described in Anderson et al. U.S. Pat. 3,287,135, issued Nov. 22, 1966; the sulfocatechols described in Kennard et al. U.S. Pat. 3,236,652, issued Feb. 22, 1966; the oximes described in Carroll et al. British Pat. 623,448; nitron; nitroindazoles; the mercaptotetrazoles described in Kendall et al. U.S. Pat. 2,403,927, issued July 16, 1946, Kennard et al. U.S. Pat. 3,266,897, issued Aug. 16, 1968, and Luckey et al. U.S. Pat. 3,397,987, issued Aug. 20, 1968; the polyvalent metal salts described in Jones U.S. Pat. 2,839,405, issued July 17, 1958; the thiuronium salts described in Herz et al. U.S. Pat. 3,220,839, issued Nov. 30, 1965; the palladium, platinum and gold salts described in Trivelli et al. U.S. Pat. 2,566,263, issued Aug. 28, 1951, and Yutzy et al. U.S. Pat. 2,597,915, issued May 27, 1952.

The photographic and other hardenable layers used in the practice of this invention can be hardened by various organic or inorganic hardeners, alone or in combination, such as the aldehydes, and blocked aldehydes, ketones, carboxylic and carbonic acid derivatives, sulfonate esters sulfonyl halides and vinyl sulfony'l ethers, active halogen compounds, epoxy compounds aziridines, active olefins, isocyanates, carbodiimides, mixed function hardeners and polymeric hardeners such as oxidized polysaccharides like dialdehyde starch and oxyguargum and the like.

The photographic emulsions and elements described in the practice of this invention can contain various colloids alone or in combination as vehicles, binding agents and various layers. Suitable hydrophilic materials include both naturally-occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric substances such as water soluble polyvinyl compounds like poly(vinylpyrrolidone), acrylamide polymers and the like.

The described photographic emulsion layers and other layers of a photographic element employed in the practice of this invention can also contain alone or in combmation with hydrophilic, water permeable colloids, other synthetic polymeric compounds such as dispersed vinyl compounds such as in latex form and particularly those which increase the dimensional stability of the photographic materials. Suitable synthetic polymers include those described, for example, in Nottorf U.S. Pat. 3,142,- 568, issued July 28, 1964; White U.S. Pat. 3,193,386, ssued July '6, 1965; Houck et al. U.S. Pat. 3,062,674, lssued Nov. '6, 1962; Houck et al. U.S. Pat. 3,220,844 issued, Nov. 30, 1965; Ream et al. U.S. Pat. 3,287,289, issued Nov. '22, 1966; and Dykstra U.S. Pat. 3,411,911, issued Nov. 19, 1968; particularly eifective are those water-insoluble polymers of alkyl acrylates and meth- 15 acrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, those which have cross-linking sites which facilitate hardening or curing, those having recurring sulfobetaine units as described in Dykstra, Canadian Pat. 774,054.

The photographic elements and emulsions used with this invention may contain antistatic or conducting layers, such layers may comprise soluble salts, e.g. chlorides, nitrates, etc., evaporated metal layers, ionic polymers such as those described in Minsk U.S. Pat. 2,861,056, issued Nov. 18, 1958 and Sterman et al. U.S. Pat. 3,206,312, issued Sept. 14, 1965, or insoluble inorganic salts such as those described in Trevoy U.S. Pat. 3,428,451, issued Feb. 18, 1969.

The photographic layers and other layers of a photographic element employed in the practice of this invention can be coated on a wide variety of supports. Typical supports include cellulose nitrate film, cellulose ester film, poly (vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and related films or resinous materials, as well as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper support, which can be partially acetylated or coated with baryta and/or an alpha-olefin polymer, particularly a polymer of an alpha-olefin containing 2 to carbon atoms such as polyethylene, polypropylene, ethylenebutene copolymers and the like.

The photographic layers employed in the practice of this invention can contain plasticizers and lubricants such as polyalcohols, e.g., glycerin and diols of the type described in Milton et al. U.S. Pat. 2,960,404, issued Nov. 1, 1966; fatty acids or esters such as those described in Robijns U.S. Pat. 2,588,765, issued Mar. 11, 1952 and Duane U.S. Pat. 3,121,060, issued Feb. 11, 1964; and silicone resins such as those described in Du Pont British Pat. 955,061.

The photographic elements employed in the practice of this invention may contain matting agents such as starch, titanium dioxide, zinc oxide, silica, polymeric beads including beads of the type described in Jelly et al. U.S. Pat. 2,992,101, issued July 11, 1961, and Lynn, U.S. Pat. 2,701,245, issued Feb. 1, 1955.

The photographic elements and emulsions used in this invention may contain brightening agents including stilbene s, triazines, oxazoles and coumarin brightening agent. Water soluble brightening agents may be used such as those described in Albers et al. German Pat. 972,067 and McFall et al. U.S. Pat. 2,933,390, issued Apr. 19, 1960, or dispersion of brighteners may be used such as those described in Jansen, German Pat. 1,150,274, Oetiker et al. U.S. Pat. 3,406,070, issued Oct. 15, 1968, and Heidke French Pat. 1,530,244.

Spectral sensitizing dyes can be used conveniently to confer additional sensitivity to light sensitive silver halide emulsions employed in the practice of this invention. For instance, additional spectral sensitization can be obtained by treating the emulsion with a solution of a sensitizing dye in an organic solvent or the dye may be added in the form of a dispersion as described in Owens et al. British Pat. 1,154,781. For optimum results, the dye may either be added to the emulsion as a final step or at some earlier stage.

Sensitizing dyes useful in sensitizing such emulsions are described, for example, in Brooker et al. U.S. Pat. 2,526,632, issued Oct. 24, 1950; Sprague U.S. Pat. 2,503,776, issued Apr. 11, 1950; Brooker et al. U.S. Pat. 2,493,748, issued Jan. 10, 1950; and Taber et al. U.S. Pat. 3,384,486, issued May 21, 1968. Spectral sensitizers which can be used include the cyanines, merocyanines, complex (tri or tetranuclear) merocyanines, complex (tri or tetranuclear) cyanines, holopolar cyanines, styryls, hemicyanines (e.g. enamine hemicyanines), oxonols and hemioxonols.

Dyes of the cyanine classes may contain such basic nuclei as the thiazolines, oxazolines, pyrrolines, pyridines,

16 oxazoles, thiazoles, selenazoles and imidazoles. Such nuclei may contain alkyl, alkylene, hydroxyalkyl, sulfoalkyl, carboxylalkyl, aminoalkyl, and enamine groups and may be fused to carbocyclic or heterocyclic ring'systems either unsubstituted or substituted with halogen, phenyl, alkyl, haloalkyl, cyano, or alkoxy groups. The dyes may be symmetrical or unsymmetrical and may contain alkyl, phenyl, enamine or heterocyclic substituents on the methine or polymethine chain.

The merocyanine dyes may contain the basic nuclei mentioned above as well as acid nuclei such as thiohydantoins, rhodanines, oxazolidenediones, thiazolidenediones, barbituric acids thiazolinones, and malononitrile. These acid nuclei may be substituted with alkyl, alkylene, phenyl, carboxyalkyl, sulfoalkyl, hydroxyalkyl, alkoxyalkyl, alkylamino groups, or heterocyclic nuclei. Combinations of these dyes may be used, if desired. In addition, supersensitizing addenda which do not absorb visible light may be included, for instance, ascorbic acid derivatives, azaindenes, cadmium salts, and organic sulfonic acids as described in McFall et al. U.S. Pat. 2,933,390, issued Apr. 19, 71960, and Jones et al. U.S. Pat. 2,937,089, issued May 17, 1960.

The various layers including the photographic layers, employed in the practice of this invention can contain light absorbing materials and filter dyes such as those described in Sawdey U.S. Pat. 3,253,921, issued May 31, 1966; Gaspar U.S. Pat. 2,274,782, issued Mar. 3, 1942; Silberstein et al. U.S. Pat. 2,527,583, issued Oct. 31, 1950; and Van Campen U.S. Pat. 2,956,879, issued Oct. 18, 1960. If desired, the dyes can be mordanted, for example, as described in Jones et al. U.S. Pat. 3,282,699, issued Nov. 1, 1966.

The photographic layers employed in the practice of this invention may contain surfactants such as saponin; anionic compounds such as the alkyl aryl sulfonates described in Baldsiefen U.S. Pat. 2,600,831, issued June 17, 1962; amphoteric compounds such as those described in Ben-Ezra U.S. Pat. 3,133,816, issued May 19, 1964; and water soluble adducts of glycidol and an alkyl phenol such as those described in Olin Mathieson British Pat. 1,022,257 8.

The photographic layers of photographic elements used in the practice of this invention may be coated by various coating procedures including dip coating, air knife coating, curtain coating, or extrusion coating using hoppers of the type described in Beguin U.S. Pat. 2,681,294, issued June 15, 1954. If desired, two or more layers may be coated simultaneously by the procedures described in Russell U.S. Pat. 2,761,791, issued Sept. 4, 1956, and Wynn British Pat. 837,095. This invention also can be used for silver halide layers coated by vacuum evaporation as described in British Pat. 968,453 and Lu Valle et al. U.S. Pat. 3,219,451, issued Nov. 23, 1965.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

What is claimed is:

1. In a photographic element comprising a support having thereon at least one photographic silver halide layer, and incorporated in said element as a silver halide developing composition the combination comprising (a) a hydrazide represented by the structural formula:

2. A photographic element of claim 1 wherein said hydrazide is 2,2-bis(hydroxymethyl)propionyl-li-phenylhydrazide.

3. A photographic element of claim 1 wherein said silver salt layer is a silver halide emulsion.

4. A photographic element of claim 3 wherein said photographic developing agent combination is present in said silver halide emulsion. g

5. A photographic element as in claim 3 wherein said hydrazide is located in said silver halide emulsion.

6. In a photographic emulsion comprising a hydrophilic binder, at least one photographic silver halide and a developing composition, the improvement wherein the developing composition in combination comprising (a) a hydrazide represented by the structural formula:

References Cited UNITED STATES PATENTS 2,419,975 5/1947 Trivelli et al 96-95 2,563,785 8/1951 Ives 96-95 3,227,552 1/1966 'Whitmore 96-3 3,447,923 6/ 1969 Jaeken 96-55 NORMAN G. TORCH'IN, Primary Examiner M. F. KELLEY, Assistant Examiner U.S. Cl. X.R. 96-67, 66, 66.3 

